This invention relates to head-set assemblies and more particularly to microphone assemblies disposed therein.
As is known in the art a head-set assembly often includes a receiver coupled to a user's ear and a microphone assembly disposed near the user's mouth. The microphone is generally provided having a body made of metal disposed in a molded, plastic microphone housing which is secured to a first end of a boom. A second end of the boom is connected to the receiver. Thus, the boom physically connects and supports the microphone and the receiver. A coaxial cable, such as a twisted pair or shielded conductors, electrically connects the microphone and the receiver. To provide the microphone assembly with an acceptable acoustic response, an acoustic foam is disposed on an inside surface of the microphone housing and the microphone is disposed in the housing and the acoustic foam is placed at least on one side thereof.
As is also known in the art, electrostatic charges typically in the range of 5 kilovolts to 20 kilovolts or more can easily accumulate on a person working in a modern office environment particularly where extensive use is made of synthetic carpeting. Thus, one problem with the head-set assembly is that such electrostatic charges which accumulate on the user of the head-set discharge from the user to the metal body of the microphone or to exposed conductors of the twisted pair wires connected to the microphone which is at a near ground potential.
The discharge thus provides an electric shock to the user and may also result in temporary or permanent damage to the microphone, the receiver or other electrical components within the head-set. Conventional microphone assemblies have not adequately avoided such electric discharge potential while preserving audio fidelity.